Under which condition is no work done? a force pushes an object and slows it down. a force pulls an object and speeds it up. a force pulls down on an object that moves downward. a force pushes up on an object that stays in place.

The correct answer is when a force pushes up on an object that stays in place under this condition no work is done.

Explanation:

A force is said to do work when there is a displacement of the object.

In the first given condition, a force pushes an object and slows it down. In this case, the work is done by the frictional force. There is a displacement of the object when the object slows it down.

In the second given condition, a force pulls an object and speeds it up. In this case, force is applied and the object start accelerated. There is a displacement when it speeds up.

In the third given condition, a force pulls down on an object that moves downward. Here, the work is done by the gravity. There is a displacement of the object when it moves downward.

In the fourth given condition, a force pushes up on an object that stays in place. As there is no displacement. No work is done in this case.

Therefore, the correct answer is when a force pushes up on an object that stays in place under this condition no work is done.

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .